The horror genre derived from gothic novels such as Mary Shelley's "Frankenstein" in 1818. Man's human nature makes us desire the feeling of fear as it gives us adrenaline so people began to write down scary stories and this developed into horror in cinema.
The 20s and 30s brought about the first films which intended to frighten an audience. Many of these films were adaptations of existing gothic novels such as: Nosferatu (1922) Frankenstein (1931) Bride of Frankenstein (1935) The Mummy (1932)